I clean my return pump every 6 months, skimmer pumps every 3 months and power heads every 3 months. Take care of your equipment and it will last longer, don't and it will fail when you need it the most. Preventative maintenance is a proven practice that works. companies all over the world have spent millions on keeping logs on equipment and figuring out just how far they can push a piece of equipment with out any maintenance before they have to do a stripe down and clean replace every thing that moves. Now they can schedule maintenance and know that they are within that critical area before breakdown save time and a tun of money. Canadian wire used to push till some thing broke then my dad started monitoring things and they could have a part shipped from Germany which took a week or so to get to Canada and then install the part that was know to break down with almost not stoppage in work as they would do the replacement on a night shift.

So the moral is do regular maintenance and you will not be sorry.

Bill